JP2611593B2 - Skin in-mold molding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a skin in-mold molding method for forming a molded body on the back surface of a skin while the skin is arranged in a mold. INDUSTRIAL APPLICABILITY The present invention can be used for molding instrument panels of automobiles, lids of glove boxes, and the like.

[0002]

2. Description of the Related Art For example, in order to form an instrument panel of an automobile, a skin previously formed into a predetermined shape from a skin material such as a polyvinyl chloride sheet by vacuum forming or the like is arranged in a mold, and the skin is formed by compression molding. A reinforcing substrate is integrally formed on the back surface side. FIG. 9 is a schematic view of a mold apparatus used for conventional skin in-mold molding. This mold includes an upper mold 100 as a fixed mold and a lower mold 200 as a movable mold. The upper die 100 holds slide cores 101 and 102.

[0003] With the upper mold 100 and the lower mold 200 opened, a skin 300 is arranged along the mold surface of the upper mold 100. Then, with the upper mold 100 and the lower mold 200 approached to some extent, the molten resin is injected into the cavity from the runner section 201 provided on the lower mold 200, and then the lower mold 200 is further driven close to the upper mold 100. Perform compression molding. Thereby, the base material 400 is integrally formed on the back surface side of the skin 300.

[0004]

However, in the above-described method for forming the skin in the mold, the treatment of the terminal portion of the skin may be problematic. That is, when the terminal of the skin is formed into a shape having a substantially U-shaped cross section, conventionally, as shown in FIG. 7, the mold surfaces of the upper die 100 and the slide core 101 are formed in a substantially U-shaped cross section, The skin 300 is arranged and molded along the shape. However, when the length of the end of the skin 300 is increased due to a cutting error or the like, the lower mold 200 interferes with the skin 300 during the compression drive as shown in FIGS. In some cases, the molding material leaked and protruded from the crevice gap, and the appearance was sometimes impaired.

The present invention has been made in view of such circumstances, and an object of the present invention is to mold a base material without a poor appearance even if a slight dimensional error occurs in the skin.

[0006]

In order to solve the above-mentioned problems, a skin in-mold molding method according to the present invention is characterized in that a skin whose end is turned into a substantially U-shaped cross section is formed along a mold surface of a first mold. In a skin in-mold molding method in which the second mold is driven so as to approach the skin and the molding material is compressed and molded between the mold surface of the second mold and the skin, the first mold is an end of the skin. The first mold has a first vertical burr cut surface extending in the mold opening and closing direction at the position of the portion, and the second mold has a second vertical burr cut surface slidingly in contact with the first vertical burr cut surface and a second vertical burr cut surface inside the second vertical burr cut surface. A vertical mold surface that is continuous with the burr cut surface and extends substantially along the mold opening / closing direction, and at least during the molding in which the second mold approaches the first mold, between the first vertical burr cut surface and the vertical mold surface A space is formed, and an end portion of the epidermis projects into the space.

[0007]

According to the method for in-mold molding of the skin of the present invention, the skin is first arranged along the mold surface of the first mold. Then, the second mold is driven close to the first mold, and the molten molding material is compressed between the mold surface of the second mold and the back surface of the skin and spread into the cavity to perform compression molding. Here, at least during molding, a space is formed between the first vertical burr cut surface of the first die and the vertical die surface of the second die. That is, when the length of the skin is longer than the standard length due to a cutting error or the like, the skin end protrudes from the first vertical burr cut surface and is in that space. Therefore, since the interference between the second mold and the skin end is prevented when the second mold is driven in proximity, the molding material can be compressed without deformation of the skin end. This prevents wrinkles at the skin end and leakage of the molding material from the skin end, thereby forming a molded body having excellent appearance quality.

[0008]

The present invention will be specifically described below with reference to examples. (Embodiment 1) FIG. 3 shows the entire structure of a mold used in this embodiment in a mold-clamped state. This mold includes an upper mold 1 as a fixed mold, a slide core 10 held by the upper mold 1 so as to be slidable in a horizontal direction, and a lower mold 2 as a fixed mold. A substantially box-shaped cavity 15 is formed between them.

The upper mold 1 has a concave mold surface 11. The slide core 10 has a first vertical burr cut surface 12 extending in a substantially vertical direction. The lower mold 2 has a second vertical burr cut surface 20 slidably in contact with the first vertical burr cut surface, an end mold surface 21 extending substantially inward from the second vertical burr cut surface 20, and an end mold surface 21. A vertical surface 22 extending substantially vertically;
And a main mold surface 23 extending horizontally inward. The lower die 2 has a nozzle touch 24 with which the nozzle of the low-pressure injection molding machine contacts, a runner 25 extending from the nozzle touch 24, and a gate 26 provided between the runner 25 and the cavity 15. .

Using the above molding die, skin in-mold molding was performed as follows. First, a skin material in which a polyvinyl chloride sheet 30 and a urethane foam 31 were laminated by lamination was prepared, cut into a predetermined size, and shaped into a predetermined box shape by vacuum forming to form a skin 3. In addition, polypropylene foam can be used instead of urethane foam.

The skin 3 is made of a polyvinyl chloride sheet 30
Are arranged on the upper die 1 so as to face the die surface 11, and the lower die 2 is driven close to the upper die 1 to bring the first vertical burr cut surface 12 and the second vertical burr cut surface 20 into sliding contact. At this time, as shown in FIG. 1, the end 32 of the skin 3 protrudes into the space 4 formed between the first vertical burr cut surface 12 and the vertical die surface 22. When the lower die 2 reaches a predetermined position, a predetermined amount of a molding material 5 (polypropylene) in a molten state is injected from the low-pressure injection molding machine into the cavity 15 via the runner 25 and the gate 26, and the lower die 2 is further compressed upward. Is done. At this time, the lower mold 2 does not interfere with the end 32 of the skin 3, and the compression drive is stopped at the position where the end mold surface 21 contacts the end 32.

In this state, as shown in FIG. 2, the molding material 5 fills the inside of the cavity 15, and the end 32 of the skin 3 is pressed against the end mold surface 21. And molding material 5 is skin 3
Of the urethane foam 31 and solidified integrally.
When a polypropylene foam is used in place of the urethane foam, they are integrated by impregnation and fusion. The obtained skin-integrated molded body was excellent in appearance quality without wrinkles or resin leakage at the end portions 32 of the skin 3. The interval between the first vertical burr cut surface 12 and the vertical die surface 22 is set in accordance with the error range of the length of the end 32 of the skin 3, and the vertical die surface 22 is formed by shaving the lower die 2 accordingly. Can be dealt with freely. (Embodiment 2) FIG. 4 is a cross-sectional view of the inside of a mold in a state where compression molding is completed in this embodiment. In this embodiment, the end face 21
The same mold as that of the first embodiment is used except that the second vertical burr cut surface 22 is continuous with the curved surface 24.

According to the skin in-mold molding method of this embodiment, the end portion 32 of the skin 3 is guided by the curved surface 24 and rolled further inward at the end of compression molding, so that the appearance quality of the end portion 32 is further improved. (Third Embodiment) For example, when manufacturing an instrument panel for an automobile, an opening for a register or the like may be formed after shaping a skin material into a predetermined shape by vacuum molding or the like. At this time, for example, if the cross-sectional shape is as shown in FIG. 5, it is preferable in terms of work to cut along the line AA. However, when this skin was subjected to conventional in-mold molding, it was difficult to dispose the skin in the mold because the end 33 was in the way. Therefore, it had to be cut along the line BB in FIG.

However, in the case of cutting along the line BB, it is difficult to cut the other portion because it interferes with the other portion, and the variation of the terminal size is increased due to the cut. For this reason, wrinkles and resin leakage may occur as described above, or a gap may occur after assembly due to an excessively large opening width. Therefore, in the present embodiment, as shown in FIG. 6, the space 4 is formed between the first vertical burr cut surface 12 and the vertical mold surface 22 even in the state where the compression molding is completed. Thereby, in-mold molding can be performed in a state where the end portion 33 is located in the space 4, so that the skin cut along the line AA in FIG. 5 can be used. Therefore, there is no wrinkle or resin leakage, and the opening width is prevented from becoming too large. Even if the error is large, a bead portion is formed at the end of the obtained molded body, and since this bead portion also has a function of concealing a gap at the time of assembly, the appearance quality is further improved.

[0015]

According to the in-mold skin molding method of the present invention, molding defects do not occur even if the accuracy of the shape of the skin becomes somewhat rough, so that the defect rate is reduced and the number of manufacturing steps is reduced. be able to. Therefore, good products can be stably manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of a mold in the middle of molding according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part of a mold in a completed molding state according to one embodiment of the present invention.

FIG. 3 is a sectional view showing a mold used in one embodiment of the present invention.

FIG. 4 is a cross-sectional view of a main part of a mold in a completed molding state according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a cutting position of an epidermis.

FIG. 6 is a cross-sectional view of a main part of a mold in a completed molding state according to a third embodiment of the present invention.

FIG. 7 is a cross-sectional view of a main part of a mold in a state during molding in a conventional molding method.

FIG. 8 is a cross-sectional view of a main part of a mold in a state where molding is completed in a conventional molding method.

FIG. 9 is a sectional view of a conventionally used mold.

[Explanation of symbols]

1: Upper type (first type) 2: Lower type (second type)
3: skin 4: space 5: molding material
10: Slide core 12: First vertical burr cut surface 20: Second vertical burr cut surface
22: Vertical surface

──────────────────────────────────────────────────続 き Continuing on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B29L 31:58 (72) Inventor Keizo Ito Kagosuga-cho, Nishi-Kasugai-gun, Aichi Prefecture 1 Ochiai-Ochiai Nagahata Toyoda Gosei (56) References JP-A-4-90334 (JP, A)

Claims (1)

(57) [Claims] 1. An outer skin having an end portion wrapped in a substantially U-shape in cross section is arranged along a mold surface of a first mold, and a second mold is driven to approach the outer skin to form the second mold. A skin in-mold molding method for compressing and molding a molding material between a mold surface of a second mold and the skin, wherein the first mold is provided at a position of an end of the skin with a first vertical burr extending in a mold opening and closing direction. The second mold has a second vertical burr cut surface slidingly in contact with the first vertical burr cut surface and the second vertical burr cut surface is continuous with the second vertical burr cut surface, and the mold opening / closing direction A vertical mold surface extending substantially along, a space is formed between the first vertical burr cut surface and the vertical mold surface at least during the molding in which the second mold approaches the first mold, A skin in-mold molding method, wherein an end of the skin protrudes into the space.